<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        header {
            height: 80px;
            background-color: rgb(138, 138, 138);
        }
    </style>
</head>

<body>
    <header>
        头部内容
    </header>
    <main>
        主题
        <img src="" alt="">
    </main>
</body>

</html>